Even as so many crises roiled the world recently, the news that a development on the Upper West Side of Manhattan would proceed with a brand of distasteful social engineering still managed to command international attention. The building, in what is known as Riverside South, a stretch of land reaching below 72nd Street that seems largely like a pop-up location for people who have never heard of Katz’s deli or the G train, had received approval from the city for separate entrances — one for wealthy residents and one for those earning far less who would occupy the project’s affordable units, in a separate wing.

This seemed to provide more evidence that living in Manhattan has become increasingly like a flight to Houston in which one is made to board in Zone 4 and eat only stale pretzels.

The “Upstairs, Downstairs” effect was permissible under a change to zoning codes made during the Bloomberg era that gave developers who provided affordable housing in market-rate projects discretion over these particulars, in addition to the considerable tax breaks they receive. Although the building’s configuration is anathema to the values embraced by the de Blasio administration, forcing the developer to abandon it would involve costly, not entirely tenable litigation, which would slow the progress of the city’s affordable-housing plans, the administration said. The focus now is to reverse the zoning change, Deputy Mayor Alicia Glen told me, a process that should take about a year.

The “poor door,” as it has been called, is an odious response to a problem whose solution is neither obvious nor easily achievable through the mechanisms of policy: How, and to what extent, should the city mandate economic integration? The Riverside development is unusual, and even vaguely radical, in the sense that its luxury units are condominiums rather than rental apartments.

Typically, buildings like it, which combine market-rate and affordable units, offer none of them for sale. In this case, a building in which apartments are trading at $2,000 a square foot will also contain 55 apartments for households earning $35,280 to $50,340 a year. (At the top range the household must contain at least four people.)

As nearly the entire Upper East Side from Lexington Avenue to Fifth can lay testament, rich people like to live among rich people. A developer erecting a structure with $3 million apartments is going to worry, not irrationally, that those apartments will be less marketable if they are next door to those renting for $1,000 a month.

It isn’t simply that rich people find poorer people yucky, though in some cases that will certainly be true, but that owners typically prefer living among other owners, out of the belief that this arrangement best protects the value of their asset. Renting has the taint of transience, diminished stability and so on.

(While only one-third of New Yorkers are homeowners, close to 60 percent of those making over $500,000 a year fall into that category, according to the Furman Center at New York University.)

So how to accomplish mingling when it can seem so at odds with the essential preferences and justifications of an entire social class? Some would argue that integration ought to be subordinate to the greater goal of simply building as much affordable housing as possible, something more easily done in parts of the city where land is farther from central quarters of wealth and power, and thus cheaper. While that kind of approach may be more economically efficient, and even ethically merited, it is hard to see it as more socially purposeful.

In an ideal universe, progressive leaders would possess marketing skills so profound that they could alter and recast our definitions of status, so that we might see the aggressive and intimate mixing of disparate populations as having its own cachet and appreciable value. Gentrification, when it doesn’t result in wholesale displacement, accomplishes this to some degree. Manhattan’s Chelsea neighborhood and Boerum Hill in Brooklyn have both witnessed significant surges in real estate prices in recent years, though both areas are home to vast public housing complexes. Multimillion-dollar brownstones and apartments are in immediate view of buildings that house the very poor.

It may be wiser to concentrate affordable-housing efforts in areas where there would at least seem to be an organic interest in economic diversity, rather than force it in less receptive places. In the end, the development at Riverside Boulevard will have generated a lot of controversy and political heat, all for the benefit of fewer than five dozen families in a city where more than 50,000 people are homeless. Better to leave some glass towers to the Real Housewives of Everywhere.